Embodiments of the present invention relate to a radio frequency identification (RFID) device, and more specifically, to a manufacturing method to reduce the footprint of a RFID tag chip and antenna assembly.
A radio frequency identification (RFID) tag chip has been widely used to automatically identify objects using a radio frequency (RF) signal. In order to automatically identify an object using the RFID tag chip, an RFID tag is first attached to the object to be identified, and an RFID reader wirelessly communicates with the RFID tag of the object in such a manner that a non-contact automatic identification scheme can be implemented. With the widespread use of such RFID technologies, the shortcomings of related automatic identification technologies, such as barcode and optical character recognition technologies, can be greatly reduced.
In recent times, the RFID tag has been widely used in physical distribution management systems, user authentication systems, electronic money (e-money), transportation systems, and the like.
For example, the physical distribution management system generally performs a classification of goods or management of goods in stock using an Integrated Circuit (IC) recording data therein, instead of using a delivery note or tag. In addition, the user authentication system generally performs an Entrance and Exit Management function using an IC card including personal information or the like.
In the meantime, a non-volatile ferroelectric memory may be used as a memory in an RFID tag.
Generally, a non-volatile ferroelectric memory, e.g., a ferroelectric Random Access Memory (FeRAM), has a data processing speed similar to that of a Dynamic Random Access Memory (DRAM). The non-volatile ferroelectric memory also preserves data even when power is turned off. Because of these properties many developers are conducting intensive research into FeRAM as a next generation memory device.
The above-mentioned FeRAM has a very similar structure to that of DRAM, and uses a ferroelectric capacitor as a memory device. The ferroelectric substance has high residual polarization characteristics, such that data is not deleted although an electric field is removed.
FIG. 1 is a block diagram illustrating a general RFID device. The RFID device according to the related art generally includes an antenna unit 1, an analog unit 10, a digital unit 20, and a memory unit 30.
In this case, the antenna unit 1 receives a radio frequency (RF) signal from an external RFID reader. The RF signal from the antenna unit 1 is input to the analog unit 10 via antenna pads 11 and 12.
The analog unit 10 amplifies the input RF signal, such that it generates a power-supply voltage VDD indicating a driving voltage of an RFID tag. The analog unit 10 detects an operation command signal from the input RF signal, and outputs a command signal CMD to the digital unit 20. In addition, the analog unit 10 detects the output voltage VDD, such that it outputs not only a power-on reset signal POR controlling a reset operation but also a clock CLK to the digital unit 20.
The digital unit 20 receives the power-supply voltage VDD, the power-on reset signal POR, the clock CLK, and the command signal CMD from the analog unit 10, and outputs a response signal RP in response to the received signals to the analog unit 10. The digital unit 20 outputs an address ADD, Input/Output data (I/O), a control signal CTR, and a clock CLK to the memory unit 30.
The memory unit 30 reads and writes data using a memory device, and stores data therein.
In this case, the RFID device uses frequencies of various bands. In general, as the value of a frequency band is lowered, the RFID device has a slower recognition speed, has a shorter operating distance, and is less affected by environments (e.g., disruption from WiFi, cellphones, etc.) In contrast, as the value of a frequency band is increased, the RFID device has a faster recognition speed, has a greater operating distance, and is considerably affected by peripheral environments.
In the meantime, an improved technology has lately attracted considerable attention where a through-hole electrode is formed so that a transmission path from an upper part to a lower part of a chip is made (i.e., the top and bottom surface of the chip can become the contact terminals of the chip). A conventional connection scheme, such as a wire bonding or a flip chip, has difficulty in reducing the size of a corresponding connection area within an RFID tag chip. That is, an additional layout space for forming a plurality of pads on a front side of a wafer is needed.